The term "virosis" refers to a group of diseases, which differ in terms of symptoms and prognosis, caused by viruses. In addition to humans, animals and plants can also be affected. In the latter case it is the branch of botany known as phytopathology that deals with it. The transmission, in the plant world, can take place in different ways and have consequences, as well as aesthetics, also at a crop level. The responsible agents have not yet been completely identified. Science has isolated over 700 species, all capable of causing infections that cause the death of the plant and therefore also substantial economic damage, especially in those areas where agriculture is an economic sector of vital importance for the local partner fabric -cheap. Plant viruses, like those that attack humans, are microorganisms invisible to the human eye against which the only effective weapons are those of prevention and hygiene, for example by carefully disinfecting the tools during pruning and grafting . In fact, effective remedies do not exist to destroy them due to their particular metabolic structure. The viruses duplicate inside the affected cell, replicating the same pattern that occurs in humans, and can have different shapes, like sticks, spherical, tubuliform. It is good to try to control the spread of those responsible for the dissemination of viroses or parasites such as aphids, mites and nematodes. The advice, in this regard, is to use a trusted store where it is possible to buy seeds and plants to be planted safely, that are not, that is, have already been infected by parasites. Another good rule is to burn the plants affected far from cultivation, in order to avoid propagating the viruses. The symptoms can be various, also depending on the virulence, the age of the host and external factors such as temperature.
Plants most at risk
The viroses they hit so many types of plants, from the vegetables that are consumed daily on the tables of Italians to those ornamental that embellish gardens, courtyards and verandas. Zucchini, cucumbers, melons, aubergines, tomatoes, peppers, legumes and then potatoes, leeks, onions, carrots and garlic seem to be more exposed to the risks of an infection. Even fruit trees are not spared by pests, especially cherry trees, almond trees, peach trees, apricot trees and plum trees. And then there are bulbous plants like narcissus, lilium, tulip, iris, gladiolus and freesia. In any case, seedlings that grow in greenhouses or tunnels seem to be particularly privileged because they create the ideal conditions for the reproduction of vectors.
If it is impossible to notice viruses, tiny micro-organisms that can only be seen under a microscope, with the naked eye, it is rather easy to ascertain the damage suffered by plants, which however should not be confused with those deriving from malnutrition, physiological alterations, toxicity and pathological situations triggered by other factors . When it is in progress a virosis leaves and flowers wither and undergo a change of form. The color fades, patches appear that sometimes take the form of a mosaic, as in the case of the cucumber and tobacco mosaic, hence the name of the pathology. Also the fruits are deformed and their consistency is spongy. In some cases, growth and reproduction stop and newborn plants appear smaller than usual sizes. Precisely for this reason viruses are among the most feared enemies of botany.
Virosis: Infection and treatment methods
Plant viruses are transmitted in different ways, as is the case for humans and animals, but contaminated gardening tools are one of the most common means of spreading the infection. However, even hands, gloves and shoes can be responsible for the spread of viral diseases, which is why attention to detail can really make the difference between a healthy plantation and a sick plantation. Another way in which micro-organisms can make plants ill are the wounds inflicted by animals, the injuries caused by pruning or poorly executed processing and the bites caused by insects that feed on the plant's sap and thus act as vectors for viruses. It seems that even "crop globalization" can be indicated among the triggers of virosis because, with the tendency to import and export vegetable varieties from abroad, perhaps not adequately controlled, a viaticum is created for the introduction and diffusion "global" of pathogens. Adequate hygiene and cleanliness of the instruments, as well as of the garments worn by the farmer, is the first rule to follow to prevent plant viruses. In fact, the only treatment consists in trying to stop the propagation of the vectors and to use plants, seeds and parts of plants of certain provenance. And at the first symptoms, contact the competent phytosanitary service in your area to carry out the necessary laboratory tests in order to ascertain the infection.
Fighting virosis is a real challenge for many farmers. If chemistry does not seem to be particularly helpful, and in any case pesticides cannot be adopted as a long-term solution, one hand comes from botany. In fact, there are plants that effectively counteract the spread of vectors. For example, sow marigold, also known as Indian carnation, in pots, and calendula helps remove nematodes. From the nature, therefore, come some valid remedies to help the plants.